Community Forums

Rooster54 · 09-05-2016, 06:51 PM

I am having problem with my Fleetwood Discovery brake air pressure warning system. Air gauge bounce around some the buzzer stays on sometime after pressure gauges are at normal position. The air pressure seam to be okay lifting the air ride and stopping the coach. The gauges go up and down before startup and the ABS lights flash. I have run the diagnostics on the ABS and it report no problems. Has anyone experience this problem?

Freightliner Chassis

jelag · 09-05-2016, 10:01 PM

On most modern chassis.... the gauges are signals from the engine ECM... the engine ECM sees these signals from sensors placed on the tanks, on the ABS, on the batteries... etc... and when the engine starts sends these signals to the dash....

Most dashes go through a quick test... that is they run all gauges to full scale and than back to zero and than start to come up based on the signal that the ECM sends the dash... so the flash up and down of the gauges and the ABS light and buzzers coming on is standard/normal....

In addition... when the key goes on.... and the engine starts and than the key drops back to the run position.... the switch sends a constant signal to the ECM... if that signal from the key is interrupted the ECM will restart the whole process....

So based on what you've written I really can't decide what's going on.... its sounds like your describing the standard key on.... engine start and self test.... in the last part of your text but I don't understand the first part...

funjnt · 09-06-2016, 06:03 AM

Morning! Air gauges are mechanical not wired through the ecm. They are plumbed so they are accurate. I am not sure of your symptoms but call a truck shop and they should be able to diagnose. I will re read your post and think about it. Not awake yet.

JFXG · 09-06-2016, 07:25 AM

Call the Freightliner Customer Assistance 24/7 hotline. 800-385-4357. They are friendly, competent, and always there.

John & Diane, fulltiming since '12 02 DS40, FL, Cat, '04 Element NHSO RVM103

slickest1 · 09-06-2016, 10:54 AM

On my coach the sending unit for the low air alarm was bad. It was located on the front air tank. there is also one on the rear tank.
That said there are also other things that hook to that buzzer. I was getting a back feed to mine that was a scratchy sound and checked and tightened all grounds. It still persisted , then one day it just stopped and I never found what caused it.
I think that same buzzer beeper on my coach sounds along with high temp and other problems that the ecm will send to it.

Like said above a call to Freightliner would be a place to start.